builtin/checkout.c

   1 #define USE_THE_INDEX_COMPATIBILITY_MACROS
   2 #include "builtin.h"
   3 #include "advice.h"
   4 #include "blob.h"
   5 #include "branch.h"
   6 #include "cache-tree.h"
   7 #include "checkout.h"
   8 #include "commit.h"
   9 #include "config.h"
  10 #include "diff.h"
  11 #include "dir.h"
  12 #include "ll-merge.h"
  13 #include "lockfile.h"
  14 #include "merge-recursive.h"
  15 #include "object-store.h"
  16 #include "parse-options.h"
  17 #include "refs.h"
  18 #include "remote.h"
  19 #include "resolve-undo.h"
  20 #include "revision.h"
  21 #include "run-command.h"
  22 #include "submodule.h"
  23 #include "submodule-config.h"
  24 #include "tree.h"
  25 #include "tree-walk.h"
  26 #include "unpack-trees.h"
  27 #include "wt-status.h"
  28 #include "xdiff-interface.h"
  29
  30 static const char * const checkout_usage[] = {
  31         N_("git checkout [<options>] <branch>"),
  32         N_("git checkout [<options>] [<branch>] -- <file>..."),
  33         NULL,
  34 };
  35
  36 static const char * const switch_branch_usage[] = {
  37         N_("git switch [<options>] [<branch>]"),
  38         NULL,
  39 };
  40
  41 static const char * const restore_usage[] = {
  42         N_("git restore [<options>] [--source=<branch>] <file>..."),
  43         NULL,
  44 };
  45
  46 struct checkout_opts {
  47         int patch_mode;
  48         int quiet;
  49         int merge;
  50         int force;
  51         int force_detach;
  52         int implicit_detach;
  53         int writeout_stage;
  54         int overwrite_ignore;
  55         int ignore_skipworktree;
  56         int ignore_other_worktrees;
  57         int show_progress;
  58         int count_checkout_paths;
  59         int overlay_mode;
  60         int dwim_new_local_branch;
  61         int discard_changes;
  62         int accept_ref;
  63         int accept_pathspec;
  64         int switch_branch_doing_nothing_is_ok;
  65         int only_merge_on_switching_branches;
  66         int can_switch_when_in_progress;
  67         int orphan_from_empty_tree;
  68         int empty_pathspec_ok;
  69         int checkout_index;
  70         int checkout_worktree;
  71         const char *ignore_unmerged_opt;
  72         int ignore_unmerged;
  73         int pathspec_file_nul;
  74         const char *pathspec_from_file;
  75
  76         const char *new_branch;
  77         const char *new_branch_force;
  78         const char *new_orphan_branch;
  79         int new_branch_log;
  80         enum branch_track track;
  81         struct diff_options diff_options;
  82         char *conflict_style;
  83
  84         int branch_exists;
  85         const char *prefix;
  86         struct pathspec pathspec;
  87         const char *from_treeish;
  88         struct tree *source_tree;
  89 };
  90
  91 struct branch_info {
  92         const char *name; /* The short name used */
  93         const char *path; /* The full name of a real branch */
  94         struct commit *commit; /* The named commit */
  95         char *refname; /* The full name of the ref being checked out. */
  96         struct object_id oid; /* The object ID of the commit being checked out. */
  97         /*
  98          * if not null the branch is detached because it's already
  99          * checked out in this checkout
 100          */
 101         char *checkout;
 102 };
 103
 104 static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
 105                               int changed)
 106 {
 107         return run_hook_le(NULL, "post-checkout",
 108                            oid_to_hex(old_commit ? &old_commit->object.oid : &null_oid),
 109                            oid_to_hex(new_commit ? &new_commit->object.oid : &null_oid),
 110                            changed ? "1" : "0", NULL);
 111         /* "new_commit" can be NULL when checking out from the index before
 112            a commit exists. */
 113
 114 }
 115
 116 static int update_some(const struct object_id *oid, struct strbuf *base,
 117                 const char *pathname, unsigned mode, int stage, void *context)
 118 {
 119         int len;
 120         struct cache_entry *ce;
 121         int pos;
 122
 123         if (S_ISDIR(mode))
 124                 return READ_TREE_RECURSIVE;
 125
 126         len = base->len + strlen(pathname);
 127         ce = make_empty_cache_entry(&the_index, len);
 128         oidcpy(&ce->oid, oid);
 129         memcpy(ce->name, base->buf, base->len);
 130         memcpy(ce->name + base->len, pathname, len - base->len);
 131         ce->ce_flags = create_ce_flags(0) | CE_UPDATE;
 132         ce->ce_namelen = len;
 133         ce->ce_mode = create_ce_mode(mode);
 134
 135         /*
 136          * If the entry is the same as the current index, we can leave the old
 137          * entry in place. Whether it is UPTODATE or not, checkout_entry will
 138          * do the right thing.
 139          */
 140         pos = cache_name_pos(ce->name, ce->ce_namelen);
 141         if (pos >= 0) {
 142                 struct cache_entry *old = active_cache[pos];
 143                 if (ce->ce_mode == old->ce_mode &&
 144                     !ce_intent_to_add(old) &&
 145                     oideq(&ce->oid, &old->oid)) {
 146                         old->ce_flags |= CE_UPDATE;
 147                         discard_cache_entry(ce);
 148                         return 0;
 149                 }
 150         }
 151
 152         add_cache_entry(ce, ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 153         return 0;
 154 }
 155
 156 static int read_tree_some(struct tree *tree, const struct pathspec *pathspec)
 157 {
 158         read_tree_recursive(the_repository, tree, "", 0, 0,
 159                             pathspec, update_some, NULL);
 160
 161         /* update the index with the given tree's info
 162          * for all args, expanding wildcards, and exit
 163          * with any non-zero return code.
 164          */
 165         return 0;
 166 }
 167
 168 static int skip_same_name(const struct cache_entry *ce, int pos)
 169 {
 170         while (++pos < active_nr &&
 171                !strcmp(active_cache[pos]->name, ce->name))
 172                 ; /* skip */
 173         return pos;
 174 }
 175
 176 static int check_stage(int stage, const struct cache_entry *ce, int pos,
 177                        int overlay_mode)
 178 {
 179         while (pos < active_nr &&
 180                !strcmp(active_cache[pos]->name, ce->name)) {
 181                 if (ce_stage(active_cache[pos]) == stage)
 182                         return 0;
 183                 pos++;
 184         }
 185         if (!overlay_mode)
 186                 return 0;
 187         if (stage == 2)
 188                 return error(_("path '%s' does not have our version"), ce->name);
 189         else
 190                 return error(_("path '%s' does not have their version"), ce->name);
 191 }
 192
 193 static int check_stages(unsigned stages, const struct cache_entry *ce, int pos)
 194 {
 195         unsigned seen = 0;
 196         const char *name = ce->name;
 197
 198         while (pos < active_nr) {
 199                 ce = active_cache[pos];
 200                 if (strcmp(name, ce->name))
 201                         break;
 202                 seen |= (1 << ce_stage(ce));
 203                 pos++;
 204         }
 205         if ((stages & seen) != stages)
 206                 return error(_("path '%s' does not have all necessary versions"),
 207                              name);
 208         return 0;
 209 }
 210
 211 static int checkout_stage(int stage, const struct cache_entry *ce, int pos,
 212                           const struct checkout *state, int *nr_checkouts,
 213                           int overlay_mode)
 214 {
 215         while (pos < active_nr &&
 216                !strcmp(active_cache[pos]->name, ce->name)) {
 217                 if (ce_stage(active_cache[pos]) == stage)
 218                         return checkout_entry(active_cache[pos], state,
 219                                               NULL, nr_checkouts);
 220                 pos++;
 221         }
 222         if (!overlay_mode) {
 223                 unlink_entry(ce);
 224                 return 0;
 225         }
 226         if (stage == 2)
 227                 return error(_("path '%s' does not have our version"), ce->name);
 228         else
 229                 return error(_("path '%s' does not have their version"), ce->name);
 230 }
 231
 232 static int checkout_merged(int pos, const struct checkout *state, int *nr_checkouts)
 233 {
 234         struct cache_entry *ce = active_cache[pos];
 235         const char *path = ce->name;
 236         mmfile_t ancestor, ours, theirs;
 237         int status;
 238         struct object_id oid;
 239         mmbuffer_t result_buf;
 240         struct object_id threeway[3];
 241         unsigned mode = 0;
 242
 243         memset(threeway, 0, sizeof(threeway));
 244         while (pos < active_nr) {
 245                 int stage;
 246                 stage = ce_stage(ce);
 247                 if (!stage || strcmp(path, ce->name))
 248                         break;
 249                 oidcpy(&threeway[stage - 1], &ce->oid);
 250                 if (stage == 2)
 251                         mode = create_ce_mode(ce->ce_mode);
 252                 pos++;
 253                 ce = active_cache[pos];
 254         }
 255         if (is_null_oid(&threeway[1]) || is_null_oid(&threeway[2]))
 256                 return error(_("path '%s' does not have necessary versions"), path);
 257
 258         read_mmblob(&ancestor, &threeway[0]);
 259         read_mmblob(&ours, &threeway[1]);
 260         read_mmblob(&theirs, &threeway[2]);
 261
 262         /*
 263          * NEEDSWORK: re-create conflicts from merges with
 264          * merge.renormalize set, too
 265          */
 266         status = ll_merge(&result_buf, path, &ancestor, "base",
 267                           &ours, "ours", &theirs, "theirs",
 268                           state->istate, NULL);
 269         free(ancestor.ptr);
 270         free(ours.ptr);
 271         free(theirs.ptr);
 272         if (status < 0 || !result_buf.ptr) {
 273                 free(result_buf.ptr);
 274                 return error(_("path '%s': cannot merge"), path);
 275         }
 276
 277         /*
 278          * NEEDSWORK:
 279          * There is absolutely no reason to write this as a blob object
 280          * and create a phony cache entry.  This hack is primarily to get
 281          * to the write_entry() machinery that massages the contents to
 282          * work-tree format and writes out which only allows it for a
 283          * cache entry.  The code in write_entry() needs to be refactored
 284          * to allow us to feed a <buffer, size, mode> instead of a cache
 285          * entry.  Such a refactoring would help merge_recursive as well
 286          * (it also writes the merge result to the object database even
 287          * when it may contain conflicts).
 288          */
 289         if (write_object_file(result_buf.ptr, result_buf.size, blob_type, &oid))
 290                 die(_("Unable to add merge result for '%s'"), path);
 291         free(result_buf.ptr);
 292         ce = make_transient_cache_entry(mode, &oid, path, 2);
 293         if (!ce)
 294                 die(_("make_cache_entry failed for path '%s'"), path);
 295         status = checkout_entry(ce, state, NULL, nr_checkouts);
 296         discard_cache_entry(ce);
 297         return status;
 298 }
 299
 300 static void mark_ce_for_checkout_overlay(struct cache_entry *ce,
 301                                          char *ps_matched,
 302                                          const struct checkout_opts *opts)
 303 {
 304         ce->ce_flags &= ~CE_MATCHED;
 305         if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 306                 return;
 307         if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 308                 /*
 309                  * "git checkout tree-ish -- path", but this entry
 310                  * is in the original index but is not in tree-ish
 311                  * or does not match the pathspec; it will not be
 312                  * checked out to the working tree.  We will not do
 313                  * anything to this entry at all.
 314                  */
 315                 return;
 316         /*
 317          * Either this entry came from the tree-ish we are
 318          * checking the paths out of, or we are checking out
 319          * of the index.
 320          *
 321          * If it comes from the tree-ish, we already know it
 322          * matches the pathspec and could just stamp
 323          * CE_MATCHED to it from update_some(). But we still
 324          * need ps_matched and read_tree_recursive (and
 325          * eventually tree_entry_interesting) cannot fill
 326          * ps_matched yet. Once it can, we can avoid calling
 327          * match_pathspec() for _all_ entries when
 328          * opts->source_tree != NULL.
 329          */
 330         if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched))
 331                 ce->ce_flags |= CE_MATCHED;
 332 }
 333
 334 static void mark_ce_for_checkout_no_overlay(struct cache_entry *ce,
 335                                             char *ps_matched,
 336                                             const struct checkout_opts *opts)
 337 {
 338         ce->ce_flags &= ~CE_MATCHED;
 339         if (!opts->ignore_skipworktree && ce_skip_worktree(ce))
 340                 return;
 341         if (ce_path_match(&the_index, ce, &opts->pathspec, ps_matched)) {
 342                 ce->ce_flags |= CE_MATCHED;
 343                 if (opts->source_tree && !(ce->ce_flags & CE_UPDATE))
 344                         /*
 345                          * In overlay mode, but the path is not in
 346                          * tree-ish, which means we should remove it
 347                          * from the index and the working tree.
 348                          */
 349                         ce->ce_flags |= CE_REMOVE | CE_WT_REMOVE;
 350         }
 351 }
 352
 353 static int checkout_worktree(const struct checkout_opts *opts,
 354                              const struct branch_info *info)
 355 {
 356         struct checkout state = CHECKOUT_INIT;
 357         int nr_checkouts = 0, nr_unmerged = 0;
 358         int errs = 0;
 359         int pos;
 360
 361         state.force = 1;
 362         state.refresh_cache = 1;
 363         state.istate = &the_index;
 364
 365         init_checkout_metadata(&state.meta, info->refname,
 366                                info->commit ? &info->commit->object.oid : &info->oid,
 367                                NULL);
 368
 369         enable_delayed_checkout(&state);
 370         for (pos = 0; pos < active_nr; pos++) {
 371                 struct cache_entry *ce = active_cache[pos];
 372                 if (ce->ce_flags & CE_MATCHED) {
 373                         if (!ce_stage(ce)) {
 374                                 errs |= checkout_entry(ce, &state,
 375                                                        NULL, &nr_checkouts);
 376                                 continue;
 377                         }
 378                         if (opts->writeout_stage)
 379                                 errs |= checkout_stage(opts->writeout_stage,
 380                                                        ce, pos,
 381                                                        &state,
 382                                                        &nr_checkouts, opts->overlay_mode);
 383                         else if (opts->merge)
 384                                 errs |= checkout_merged(pos, &state,
 385                                                         &nr_unmerged);
 386                         pos = skip_same_name(ce, pos) - 1;
 387                 }
 388         }
 389         remove_marked_cache_entries(&the_index, 1);
 390         remove_scheduled_dirs();
 391         errs |= finish_delayed_checkout(&state, &nr_checkouts);
 392
 393         if (opts->count_checkout_paths) {
 394                 if (nr_unmerged)
 395                         fprintf_ln(stderr, Q_("Recreated %d merge conflict",
 396                                               "Recreated %d merge conflicts",
 397                                               nr_unmerged),
 398                                    nr_unmerged);
 399                 if (opts->source_tree)
 400                         fprintf_ln(stderr, Q_("Updated %d path from %s",
 401                                               "Updated %d paths from %s",
 402                                               nr_checkouts),
 403                                    nr_checkouts,
 404                                    find_unique_abbrev(&opts->source_tree->object.oid,
 405                                                       DEFAULT_ABBREV));
 406                 else if (!nr_unmerged || nr_checkouts)
 407                         fprintf_ln(stderr, Q_("Updated %d path from the index",
 408                                               "Updated %d paths from the index",
 409                                               nr_checkouts),
 410                                    nr_checkouts);
 411         }
 412
 413         return errs;
 414 }
 415
 416 static int checkout_paths(const struct checkout_opts *opts,
 417                           const struct branch_info *new_branch_info)
 418 {
 419         int pos;
 420         static char *ps_matched;
 421         struct object_id rev;
 422         struct commit *head;
 423         int errs = 0;
 424         struct lock_file lock_file = LOCK_INIT;
 425         int checkout_index;
 426
 427         trace2_cmd_mode(opts->patch_mode ? "patch" : "path");
 428
 429         if (opts->track != BRANCH_TRACK_UNSPECIFIED)
 430                 die(_("'%s' cannot be used with updating paths"), "--track");
 431
 432         if (opts->new_branch_log)
 433                 die(_("'%s' cannot be used with updating paths"), "-l");
 434
 435         if (opts->ignore_unmerged && opts->patch_mode)
 436                 die(_("'%s' cannot be used with updating paths"),
 437                     opts->ignore_unmerged_opt);
 438
 439         if (opts->force_detach)
 440                 die(_("'%s' cannot be used with updating paths"), "--detach");
 441
 442         if (opts->merge && opts->patch_mode)
 443                 die(_("'%s' cannot be used with %s"), "--merge", "--patch");
 444
 445         if (opts->ignore_unmerged && opts->merge)
 446                 die(_("'%s' cannot be used with %s"),
 447                     opts->ignore_unmerged_opt, "-m");
 448
 449         if (opts->new_branch)
 450                 die(_("Cannot update paths and switch to branch '%s' at the same time."),
 451                     opts->new_branch);
 452
 453         if (!opts->checkout_worktree && !opts->checkout_index)
 454                 die(_("neither '%s' or '%s' is specified"),
 455                     "--staged", "--worktree");
 456
 457         if (!opts->checkout_worktree && !opts->from_treeish)
 458                 die(_("'%s' must be used when '%s' is not specified"),
 459                     "--worktree", "--source");
 460
 461         if (opts->checkout_index && !opts->checkout_worktree &&
 462             opts->writeout_stage)
 463                 die(_("'%s' or '%s' cannot be used with %s"),
 464                     "--ours", "--theirs", "--staged");
 465
 466         if (opts->checkout_index && !opts->checkout_worktree &&
 467             opts->merge)
 468                 die(_("'%s' or '%s' cannot be used with %s"),
 469                     "--merge", "--conflict", "--staged");
 470
 471         if (opts->patch_mode) {
 472                 const char *patch_mode;
 473
 474                 if (opts->checkout_index && opts->checkout_worktree)
 475                         patch_mode = "--patch=checkout";
 476                 else if (opts->checkout_index && !opts->checkout_worktree)
 477                         patch_mode = "--patch=reset";
 478                 else if (!opts->checkout_index && opts->checkout_worktree)
 479                         patch_mode = "--patch=worktree";
 480                 else
 481                         BUG("either flag must have been set, worktree=%d, index=%d",
 482                             opts->checkout_worktree, opts->checkout_index);
 483                 return run_add_interactive(new_branch_info->name, patch_mode, &opts->pathspec);
 484         }
 485
 486         repo_hold_locked_index(the_repository, &lock_file, LOCK_DIE_ON_ERROR);
 487         if (read_cache_preload(&opts->pathspec) < 0)
 488                 return error(_("index file corrupt"));
 489
 490         if (opts->source_tree)
 491                 read_tree_some(opts->source_tree, &opts->pathspec);
 492
 493         ps_matched = xcalloc(opts->pathspec.nr, 1);
 494
 495         /*
 496          * Make sure all pathspecs participated in locating the paths
 497          * to be checked out.
 498          */
 499         for (pos = 0; pos < active_nr; pos++)
 500                 if (opts->overlay_mode)
 501                         mark_ce_for_checkout_overlay(active_cache[pos],
 502                                                      ps_matched,
 503                                                      opts);
 504                 else
 505                         mark_ce_for_checkout_no_overlay(active_cache[pos],
 506                                                         ps_matched,
 507                                                         opts);
 508
 509         if (report_path_error(ps_matched, &opts->pathspec)) {
 510                 free(ps_matched);
 511                 return 1;
 512         }
 513         free(ps_matched);
 514
 515         /* "checkout -m path" to recreate conflicted state */
 516         if (opts->merge)
 517                 unmerge_marked_index(&the_index);
 518
 519         /* Any unmerged paths? */
 520         for (pos = 0; pos < active_nr; pos++) {
 521                 const struct cache_entry *ce = active_cache[pos];
 522                 if (ce->ce_flags & CE_MATCHED) {
 523                         if (!ce_stage(ce))
 524                                 continue;
 525                         if (opts->ignore_unmerged) {
 526                                 if (!opts->quiet)
 527                                         warning(_("path '%s' is unmerged"), ce->name);
 528                         } else if (opts->writeout_stage) {
 529                                 errs |= check_stage(opts->writeout_stage, ce, pos, opts->overlay_mode);
 530                         } else if (opts->merge) {
 531                                 errs |= check_stages((1<<2) | (1<<3), ce, pos);
 532                         } else {
 533                                 errs = 1;
 534                                 error(_("path '%s' is unmerged"), ce->name);
 535                         }
 536                         pos = skip_same_name(ce, pos) - 1;
 537                 }
 538         }
 539         if (errs)
 540                 return 1;
 541
 542         /* Now we are committed to check them out */
 543         if (opts->checkout_worktree)
 544                 errs |= checkout_worktree(opts, new_branch_info);
 545         else
 546                 remove_marked_cache_entries(&the_index, 1);
 547
 548         /*
 549          * Allow updating the index when checking out from the index.
 550          * This is to save new stat info.
 551          */
 552         if (opts->checkout_worktree && !opts->checkout_index && !opts->source_tree)
 553                 checkout_index = 1;
 554         else
 555                 checkout_index = opts->checkout_index;
 556
 557         if (checkout_index) {
 558                 if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 559                         die(_("unable to write new index file"));
 560         } else {
 561                 /*
 562                  * NEEDSWORK: if --worktree is not specified, we
 563                  * should save stat info of checked out files in the
 564                  * index to avoid the next (potentially costly)
 565                  * refresh. But it's a bit tricker to do...
 566                  */
 567                 rollback_lock_file(&lock_file);
 568         }
 569
 570         read_ref_full("HEAD", 0, &rev, NULL);
 571         head = lookup_commit_reference_gently(the_repository, &rev, 1);
 572
 573         errs |= post_checkout_hook(head, head, 0);
 574         return errs;
 575 }
 576
 577 static void show_local_changes(struct object *head,
 578                                const struct diff_options *opts)
 579 {
 580         struct rev_info rev;
 581         /* I think we want full paths, even if we're in a subdirectory. */
 582         repo_init_revisions(the_repository, &rev, NULL);
 583         rev.diffopt.flags = opts->flags;
 584         rev.diffopt.output_format |= DIFF_FORMAT_NAME_STATUS;
 585         diff_setup_done(&rev.diffopt);
 586         add_pending_object(&rev, head, NULL);
 587         run_diff_index(&rev, 0);
 588 }
 589
 590 static void describe_detached_head(const char *msg, struct commit *commit)
 591 {
 592         struct strbuf sb = STRBUF_INIT;
 593
 594         if (!parse_commit(commit))
 595                 pp_commit_easy(CMIT_FMT_ONELINE, commit, &sb);
 596         if (print_sha1_ellipsis()) {
 597                 fprintf(stderr, "%s %s... %s\n", msg,
 598                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 599         } else {
 600                 fprintf(stderr, "%s %s %s\n", msg,
 601                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV), sb.buf);
 602         }
 603         strbuf_release(&sb);
 604 }
 605
 606 static int reset_tree(struct tree *tree, const struct checkout_opts *o,
 607                       int worktree, int *writeout_error,
 608                       struct branch_info *info)
 609 {
 610         struct unpack_trees_options opts;
 611         struct tree_desc tree_desc;
 612
 613         memset(&opts, 0, sizeof(opts));
 614         opts.head_idx = -1;
 615         opts.update = worktree;
 616         opts.skip_unmerged = !worktree;
 617         opts.reset = 1;
 618         opts.merge = 1;
 619         opts.fn = oneway_merge;
 620         opts.verbose_update = o->show_progress;
 621         opts.src_index = &the_index;
 622         opts.dst_index = &the_index;
 623         init_checkout_metadata(&opts.meta, info->refname,
 624                                info->commit ? &info->commit->object.oid : &null_oid,
 625                                NULL);
 626         parse_tree(tree);
 627         init_tree_desc(&tree_desc, tree->buffer, tree->size);
 628         switch (unpack_trees(1, &tree_desc, &opts)) {
 629         case -2:
 630                 *writeout_error = 1;
 631                 /*
 632                  * We return 0 nevertheless, as the index is all right
 633                  * and more importantly we have made best efforts to
 634                  * update paths in the work tree, and we cannot revert
 635                  * them.
 636                  */
 637                 /* fallthrough */
 638         case 0:
 639                 return 0;
 640         default:
 641                 return 128;
 642         }
 643 }
 644
 645 static void setup_branch_path(struct branch_info *branch)
 646 {
 647         struct strbuf buf = STRBUF_INIT;
 648
 649         /*
 650          * If this is a ref, resolve it; otherwise, look up the OID for our
 651          * expression.  Failure here is okay.
 652          */
 653         if (!dwim_ref(branch->name, strlen(branch->name), &branch->oid, &branch->refname))
 654                 repo_get_oid_committish(the_repository, branch->name, &branch->oid);
 655
 656         strbuf_branchname(&buf, branch->name, INTERPRET_BRANCH_LOCAL);
 657         if (strcmp(buf.buf, branch->name))
 658                 branch->name = xstrdup(buf.buf);
 659         strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 660         branch->path = strbuf_detach(&buf, NULL);
 661 }
 662
 663 static int merge_working_tree(const struct checkout_opts *opts,
 664                               struct branch_info *old_branch_info,
 665                               struct branch_info *new_branch_info,
 666                               int *writeout_error)
 667 {
 668         int ret;
 669         struct lock_file lock_file = LOCK_INIT;
 670         struct tree *new_tree;
 671
 672         hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
 673         if (read_cache_preload(NULL) < 0)
 674                 return error(_("index file corrupt"));
 675
 676         resolve_undo_clear();
 677         if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
 678                 if (new_branch_info->commit)
 679                         BUG("'switch --orphan' should never accept a commit as starting point");
 680                 new_tree = parse_tree_indirect(the_hash_algo->empty_tree);
 681         } else
 682                 new_tree = get_commit_tree(new_branch_info->commit);
 683         if (opts->discard_changes) {
 684                 ret = reset_tree(new_tree, opts, 1, writeout_error, new_branch_info);
 685                 if (ret)
 686                         return ret;
 687         } else {
 688                 struct tree_desc trees[2];
 689                 struct tree *tree;
 690                 struct unpack_trees_options topts;
 691
 692                 memset(&topts, 0, sizeof(topts));
 693                 topts.head_idx = -1;
 694                 topts.src_index = &the_index;
 695                 topts.dst_index = &the_index;
 696
 697                 setup_unpack_trees_porcelain(&topts, "checkout");
 698
 699                 refresh_cache(REFRESH_QUIET);
 700
 701                 if (unmerged_cache()) {
 702                         error(_("you need to resolve your current index first"));
 703                         return 1;
 704                 }
 705
 706                 /* 2-way merge to the new branch */
 707                 topts.initial_checkout = is_cache_unborn();
 708                 topts.update = 1;
 709                 topts.merge = 1;
 710                 topts.quiet = opts->merge && old_branch_info->commit;
 711                 topts.verbose_update = opts->show_progress;
 712                 topts.fn = twoway_merge;
 713                 init_checkout_metadata(&topts.meta, new_branch_info->refname,
 714                                        new_branch_info->commit ?
 715                                        &new_branch_info->commit->object.oid :
 716                                        &new_branch_info->oid, NULL);
 717                 if (opts->overwrite_ignore) {
 718                         topts.dir = xcalloc(1, sizeof(*topts.dir));
 719                         topts.dir->flags |= DIR_SHOW_IGNORED;
 720                         setup_standard_excludes(topts.dir);
 721                 }
 722                 tree = parse_tree_indirect(old_branch_info->commit ?
 723                                            &old_branch_info->commit->object.oid :
 724                                            the_hash_algo->empty_tree);
 725                 init_tree_desc(&trees[0], tree->buffer, tree->size);
 726                 parse_tree(new_tree);
 727                 tree = new_tree;
 728                 init_tree_desc(&trees[1], tree->buffer, tree->size);
 729
 730                 ret = unpack_trees(2, trees, &topts);
 731                 clear_unpack_trees_porcelain(&topts);
 732                 if (ret == -1) {
 733                         /*
 734                          * Unpack couldn't do a trivial merge; either
 735                          * give up or do a real merge, depending on
 736                          * whether the merge flag was used.
 737                          */
 738                         struct tree *work;
 739                         struct tree *old_tree;
 740                         struct merge_options o;
 741                         struct strbuf sb = STRBUF_INIT;
 742                         struct strbuf old_commit_shortname = STRBUF_INIT;
 743
 744                         if (!opts->merge)
 745                                 return 1;
 746
 747                         /*
 748                          * Without old_branch_info->commit, the below is the same as
 749                          * the two-tree unpack we already tried and failed.
 750                          */
 751                         if (!old_branch_info->commit)
 752                                 return 1;
 753                         old_tree = get_commit_tree(old_branch_info->commit);
 754
 755                         if (repo_index_has_changes(the_repository, old_tree, &sb))
 756                                 die(_("cannot continue with staged changes in "
 757                                       "the following files:\n%s"), sb.buf);
 758                         strbuf_release(&sb);
 759
 760                         /* Do more real merge */
 761
 762                         /*
 763                          * We update the index fully, then write the
 764                          * tree from the index, then merge the new
 765                          * branch with the current tree, with the old
 766                          * branch as the base. Then we reset the index
 767                          * (but not the working tree) to the new
 768                          * branch, leaving the working tree as the
 769                          * merged version, but skipping unmerged
 770                          * entries in the index.
 771                          */
 772
 773                         add_files_to_cache(NULL, NULL, 0);
 774                         /*
 775                          * NEEDSWORK: carrying over local changes
 776                          * when branches have different end-of-line
 777                          * normalization (or clean+smudge rules) is
 778                          * a pain; plumb in an option to set
 779                          * o.renormalize?
 780                          */
 781                         init_merge_options(&o, the_repository);
 782                         o.verbosity = 0;
 783                         work = write_in_core_index_as_tree(the_repository);
 784
 785                         ret = reset_tree(new_tree,
 786                                          opts, 1,
 787                                          writeout_error, new_branch_info);
 788                         if (ret)
 789                                 return ret;
 790                         o.ancestor = old_branch_info->name;
 791                         if (old_branch_info->name == NULL) {
 792                                 strbuf_add_unique_abbrev(&old_commit_shortname,
 793                                                          &old_branch_info->commit->object.oid,
 794                                                          DEFAULT_ABBREV);
 795                                 o.ancestor = old_commit_shortname.buf;
 796                         }
 797                         o.branch1 = new_branch_info->name;
 798                         o.branch2 = "local";
 799                         ret = merge_trees(&o,
 800                                           new_tree,
 801                                           work,
 802                                           old_tree);
 803                         if (ret < 0)
 804                                 exit(128);
 805                         ret = reset_tree(new_tree,
 806                                          opts, 0,
 807                                          writeout_error, new_branch_info);
 808                         strbuf_release(&o.obuf);
 809                         strbuf_release(&old_commit_shortname);
 810                         if (ret)
 811                                 return ret;
 812                 }
 813         }
 814
 815         if (!active_cache_tree)
 816                 active_cache_tree = cache_tree();
 817
 818         if (!cache_tree_fully_valid(active_cache_tree))
 819                 cache_tree_update(&the_index, WRITE_TREE_SILENT | WRITE_TREE_REPAIR);
 820
 821         if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 822                 die(_("unable to write new index file"));
 823
 824         if (!opts->discard_changes && !opts->quiet && new_branch_info->commit)
 825                 show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
 826
 827         return 0;
 828 }
 829
 830 static void report_tracking(struct branch_info *new_branch_info)
 831 {
 832         struct strbuf sb = STRBUF_INIT;
 833         struct branch *branch = branch_get(new_branch_info->name);
 834
 835         if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL))
 836                 return;
 837         fputs(sb.buf, stdout);
 838         strbuf_release(&sb);
 839 }
 840
 841 static void update_refs_for_switch(const struct checkout_opts *opts,
 842                                    struct branch_info *old_branch_info,
 843                                    struct branch_info *new_branch_info)
 844 {
 845         struct strbuf msg = STRBUF_INIT;
 846         const char *old_desc, *reflog_msg;
 847         if (opts->new_branch) {
 848                 if (opts->new_orphan_branch) {
 849                         char *refname;
 850
 851                         refname = mkpathdup("refs/heads/%s", opts->new_orphan_branch);
 852                         if (opts->new_branch_log &&
 853                             !should_autocreate_reflog(refname)) {
 854                                 int ret;
 855                                 struct strbuf err = STRBUF_INIT;
 856
 857                                 ret = safe_create_reflog(refname, 1, &err);
 858                                 if (ret) {
 859                                         fprintf(stderr, _("Can not do reflog for '%s': %s\n"),
 860                                                 opts->new_orphan_branch, err.buf);
 861                                         strbuf_release(&err);
 862                                         free(refname);
 863                                         return;
 864                                 }
 865                                 strbuf_release(&err);
 866                         }
 867                         free(refname);
 868                 }
 869                 else
 870                         create_branch(the_repository,
 871                                       opts->new_branch, new_branch_info->name,
 872                                       opts->new_branch_force ? 1 : 0,
 873                                       opts->new_branch_force ? 1 : 0,
 874                                       opts->new_branch_log,
 875                                       opts->quiet,
 876                                       opts->track);
 877                 new_branch_info->name = opts->new_branch;
 878                 setup_branch_path(new_branch_info);
 879         }
 880
 881         old_desc = old_branch_info->name;
 882         if (!old_desc && old_branch_info->commit)
 883                 old_desc = oid_to_hex(&old_branch_info->commit->object.oid);
 884
 885         reflog_msg = getenv("GIT_REFLOG_ACTION");
 886         if (!reflog_msg)
 887                 strbuf_addf(&msg, "checkout: moving from %s to %s",
 888                         old_desc ? old_desc : "(invalid)", new_branch_info->name);
 889         else
 890                 strbuf_insertstr(&msg, 0, reflog_msg);
 891
 892         if (!strcmp(new_branch_info->name, "HEAD") && !new_branch_info->path && !opts->force_detach) {
 893                 /* Nothing to do. */
 894         } else if (opts->force_detach || !new_branch_info->path) {      /* No longer on any branch. */
 895                 update_ref(msg.buf, "HEAD", &new_branch_info->commit->object.oid, NULL,
 896                            REF_NO_DEREF, UPDATE_REFS_DIE_ON_ERR);
 897                 if (!opts->quiet) {
 898                         if (old_branch_info->path &&
 899                             advice_detached_head && !opts->force_detach)
 900                                 detach_advice(new_branch_info->name);
 901                         describe_detached_head(_("HEAD is now at"), new_branch_info->commit);
 902                 }
 903         } else if (new_branch_info->path) {     /* Switch branches. */
 904                 if (create_symref("HEAD", new_branch_info->path, msg.buf) < 0)
 905                         die(_("unable to update HEAD"));
 906                 if (!opts->quiet) {
 907                         if (old_branch_info->path && !strcmp(new_branch_info->path, old_branch_info->path)) {
 908                                 if (opts->new_branch_force)
 909                                         fprintf(stderr, _("Reset branch '%s'\n"),
 910                                                 new_branch_info->name);
 911                                 else
 912                                         fprintf(stderr, _("Already on '%s'\n"),
 913                                                 new_branch_info->name);
 914                         } else if (opts->new_branch) {
 915                                 if (opts->branch_exists)
 916                                         fprintf(stderr, _("Switched to and reset branch '%s'\n"), new_branch_info->name);
 917                                 else
 918                                         fprintf(stderr, _("Switched to a new branch '%s'\n"), new_branch_info->name);
 919                         } else {
 920                                 fprintf(stderr, _("Switched to branch '%s'\n"),
 921                                         new_branch_info->name);
 922                         }
 923                 }
 924                 if (old_branch_info->path && old_branch_info->name) {
 925                         if (!ref_exists(old_branch_info->path) && reflog_exists(old_branch_info->path))
 926                                 delete_reflog(old_branch_info->path);
 927                 }
 928         }
 929         remove_branch_state(the_repository, !opts->quiet);
 930         strbuf_release(&msg);
 931         if (!opts->quiet &&
 932             (new_branch_info->path || (!opts->force_detach && !strcmp(new_branch_info->name, "HEAD"))))
 933                 report_tracking(new_branch_info);
 934 }
 935
 936 static int add_pending_uninteresting_ref(const char *refname,
 937                                          const struct object_id *oid,
 938                                          int flags, void *cb_data)
 939 {
 940         add_pending_oid(cb_data, refname, oid, UNINTERESTING);
 941         return 0;
 942 }
 943
 944 static void describe_one_orphan(struct strbuf *sb, struct commit *commit)
 945 {
 946         strbuf_addstr(sb, "  ");
 947         strbuf_add_unique_abbrev(sb, &commit->object.oid, DEFAULT_ABBREV);
 948         strbuf_addch(sb, ' ');
 949         if (!parse_commit(commit))
 950                 pp_commit_easy(CMIT_FMT_ONELINE, commit, sb);
 951         strbuf_addch(sb, '\n');
 952 }
 953
 954 #define ORPHAN_CUTOFF 4
 955 static void suggest_reattach(struct commit *commit, struct rev_info *revs)
 956 {
 957         struct commit *c, *last = NULL;
 958         struct strbuf sb = STRBUF_INIT;
 959         int lost = 0;
 960         while ((c = get_revision(revs)) != NULL) {
 961                 if (lost < ORPHAN_CUTOFF)
 962                         describe_one_orphan(&sb, c);
 963                 last = c;
 964                 lost++;
 965         }
 966         if (ORPHAN_CUTOFF < lost) {
 967                 int more = lost - ORPHAN_CUTOFF;
 968                 if (more == 1)
 969                         describe_one_orphan(&sb, last);
 970                 else
 971                         strbuf_addf(&sb, _(" ... and %d more.\n"), more);
 972         }
 973
 974         fprintf(stderr,
 975                 Q_(
 976                 /* The singular version */
 977                 "Warning: you are leaving %d commit behind, "
 978                 "not connected to\n"
 979                 "any of your branches:\n\n"
 980                 "%s\n",
 981                 /* The plural version */
 982                 "Warning: you are leaving %d commits behind, "
 983                 "not connected to\n"
 984                 "any of your branches:\n\n"
 985                 "%s\n",
 986                 /* Give ngettext() the count */
 987                 lost),
 988                 lost,
 989                 sb.buf);
 990         strbuf_release(&sb);
 991
 992         if (advice_detached_head)
 993                 fprintf(stderr,
 994                         Q_(
 995                         /* The singular version */
 996                         "If you want to keep it by creating a new branch, "
 997                         "this may be a good time\nto do so with:\n\n"
 998                         " git branch <new-branch-name> %s\n\n",
 999                         /* The plural version */
1000                         "If you want to keep them by creating a new branch, "
1001                         "this may be a good time\nto do so with:\n\n"
1002                         " git branch <new-branch-name> %s\n\n",
1003                         /* Give ngettext() the count */
1004                         lost),
1005                         find_unique_abbrev(&commit->object.oid, DEFAULT_ABBREV));
1006 }
1007
1008 /*
1009  * We are about to leave commit that was at the tip of a detached
1010  * HEAD.  If it is not reachable from any ref, this is the last chance
1011  * for the user to do so without resorting to reflog.
1012  */
1013 static void orphaned_commit_warning(struct commit *old_commit, struct commit *new_commit)
1014 {
1015         struct rev_info revs;
1016         struct object *object = &old_commit->object;
1017
1018         repo_init_revisions(the_repository, &revs, NULL);
1019         setup_revisions(0, NULL, &revs, NULL);
1020
1021         object->flags &= ~UNINTERESTING;
1022         add_pending_object(&revs, object, oid_to_hex(&object->oid));
1023
1024         for_each_ref(add_pending_uninteresting_ref, &revs);
1025         if (new_commit)
1026                 add_pending_oid(&revs, "HEAD",
1027                                 &new_commit->object.oid,
1028                                 UNINTERESTING);
1029
1030         if (prepare_revision_walk(&revs))
1031                 die(_("internal error in revision walk"));
1032         if (!(old_commit->object.flags & UNINTERESTING))
1033                 suggest_reattach(old_commit, &revs);
1034         else
1035                 describe_detached_head(_("Previous HEAD position was"), old_commit);
1036
1037         /* Clean up objects used, as they will be reused. */
1038         clear_commit_marks_all(ALL_REV_FLAGS);
1039 }
1040
1041 static int switch_branches(const struct checkout_opts *opts,
1042                            struct branch_info *new_branch_info)
1043 {
1044         int ret = 0;
1045         struct branch_info old_branch_info;
1046         void *path_to_free;
1047         struct object_id rev;
1048         int flag, writeout_error = 0;
1049         int do_merge = 1;
1050
1051         trace2_cmd_mode("branch");
1052
1053         memset(&old_branch_info, 0, sizeof(old_branch_info));
1054         old_branch_info.path = path_to_free = resolve_refdup("HEAD", 0, &rev, &flag);
1055         if (old_branch_info.path)
1056                 old_branch_info.commit = lookup_commit_reference_gently(the_repository, &rev, 1);
1057         if (!(flag & REF_ISSYMREF))
1058                 old_branch_info.path = NULL;
1059
1060         if (old_branch_info.path)
1061                 skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
1062
1063         if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
1064                 if (new_branch_info->name)
1065                         BUG("'switch --orphan' should never accept a commit as starting point");
1066                 new_branch_info->commit = NULL;
1067                 new_branch_info->name = "(empty)";
1068                 do_merge = 1;
1069         }
1070
1071         if (!new_branch_info->name) {
1072                 new_branch_info->name = "HEAD";
1073                 new_branch_info->commit = old_branch_info.commit;
1074                 if (!new_branch_info->commit)
1075                         die(_("You are on a branch yet to be born"));
1076                 parse_commit_or_die(new_branch_info->commit);
1077
1078                 if (opts->only_merge_on_switching_branches)
1079                         do_merge = 0;
1080         }
1081
1082         if (do_merge) {
1083                 ret = merge_working_tree(opts, &old_branch_info, new_branch_info, &writeout_error);
1084                 if (ret) {
1085                         free(path_to_free);
1086                         return ret;
1087                 }
1088         }
1089
1090         if (!opts->quiet && !old_branch_info.path && old_branch_info.commit && new_branch_info->commit != old_branch_info.commit)
1091                 orphaned_commit_warning(old_branch_info.commit, new_branch_info->commit);
1092
1093         update_refs_for_switch(opts, &old_branch_info, new_branch_info);
1094
1095         ret = post_checkout_hook(old_branch_info.commit, new_branch_info->commit, 1);
1096         free(path_to_free);
1097         return ret || writeout_error;
1098 }
1099
1100 static int git_checkout_config(const char *var, const char *value, void *cb)
1101 {
1102         if (!strcmp(var, "diff.ignoresubmodules")) {
1103                 struct checkout_opts *opts = cb;
1104                 handle_ignore_submodules_arg(&opts->diff_options, value);
1105                 return 0;
1106         }
1107
1108         if (starts_with(var, "submodule."))
1109                 return git_default_submodule_config(var, value, NULL);
1110
1111         return git_xmerge_config(var, value, NULL);
1112 }
1113
1114 static void setup_new_branch_info_and_source_tree(
1115         struct branch_info *new_branch_info,
1116         struct checkout_opts *opts,
1117         struct object_id *rev,
1118         const char *arg)
1119 {
1120         struct tree **source_tree = &opts->source_tree;
1121         struct object_id branch_rev;
1122
1123         new_branch_info->name = arg;
1124         setup_branch_path(new_branch_info);
1125
1126         if (!check_refname_format(new_branch_info->path, 0) &&
1127             !read_ref(new_branch_info->path, &branch_rev))
1128                 oidcpy(rev, &branch_rev);
1129         else
1130                 new_branch_info->path = NULL; /* not an existing branch */
1131
1132         new_branch_info->commit = lookup_commit_reference_gently(the_repository, rev, 1);
1133         if (!new_branch_info->commit) {
1134                 /* not a commit */
1135                 *source_tree = parse_tree_indirect(rev);
1136         } else {
1137                 parse_commit_or_die(new_branch_info->commit);
1138                 *source_tree = get_commit_tree(new_branch_info->commit);
1139         }
1140 }
1141
1142 static const char *parse_remote_branch(const char *arg,
1143                                        struct object_id *rev,
1144                                        int could_be_checkout_paths)
1145 {
1146         int num_matches = 0;
1147         const char *remote = unique_tracking_name(arg, rev, &num_matches);
1148
1149         if (remote && could_be_checkout_paths) {
1150                 die(_("'%s' could be both a local file and a tracking branch.\n"
1151                         "Please use -- (and optionally --no-guess) to disambiguate"),
1152                     arg);
1153         }
1154
1155         if (!remote && num_matches > 1) {
1156             if (advice_checkout_ambiguous_remote_branch_name) {
1157                     advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
1158                              "you can do so by fully qualifying the name with the --track option:\n"
1159                              "\n"
1160                              "    git checkout --track origin/<name>\n"
1161                              "\n"
1162                              "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
1163                              "one remote, e.g. the 'origin' remote, consider setting\n"
1164                              "checkout.defaultRemote=origin in your config."));
1165             }
1166
1167             die(_("'%s' matched multiple (%d) remote tracking branches"),
1168                 arg, num_matches);
1169         }
1170
1171         return remote;
1172 }
1173
1174 static int parse_branchname_arg(int argc, const char **argv,
1175                                 int dwim_new_local_branch_ok,
1176                                 struct branch_info *new_branch_info,
1177                                 struct checkout_opts *opts,
1178                                 struct object_id *rev)
1179 {
1180         const char **new_branch = &opts->new_branch;
1181         int argcount = 0;
1182         const char *arg;
1183         int dash_dash_pos;
1184         int has_dash_dash = 0;
1185         int i;
1186
1187         /*
1188          * case 1: git checkout <ref> -- [<paths>]
1189          *
1190          *   <ref> must be a valid tree, everything after the '--' must be
1191          *   a path.
1192          *
1193          * case 2: git checkout -- [<paths>]
1194          *
1195          *   everything after the '--' must be paths.
1196          *
1197          * case 3: git checkout <something> [--]
1198          *
1199          *   (a) If <something> is a commit, that is to
1200          *       switch to the branch or detach HEAD at it.  As a special case,
1201          *       if <something> is A...B (missing A or B means HEAD but you can
1202          *       omit at most one side), and if there is a unique merge base
1203          *       between A and B, A...B names that merge base.
1204          *
1205          *   (b) If <something> is _not_ a commit, either "--" is present
1206          *       or <something> is not a path, no -t or -b was given, and
1207          *       and there is a tracking branch whose name is <something>
1208          *       in one and only one remote (or if the branch exists on the
1209          *       remote named in checkout.defaultRemote), then this is a
1210          *       short-hand to fork local <something> from that
1211          *       remote-tracking branch.
1212          *
1213          *   (c) Otherwise, if "--" is present, treat it like case (1).
1214          *
1215          *   (d) Otherwise :
1216          *       - if it's a reference, treat it like case (1)
1217          *       - else if it's a path, treat it like case (2)
1218          *       - else: fail.
1219          *
1220          * case 4: git checkout <something> <paths>
1221          *
1222          *   The first argument must not be ambiguous.
1223          *   - If it's *only* a reference, treat it like case (1).
1224          *   - If it's only a path, treat it like case (2).
1225          *   - else: fail.
1226          *
1227          */
1228         if (!argc)
1229                 return 0;
1230
1231         if (!opts->accept_pathspec) {
1232                 if (argc > 1)
1233                         die(_("only one reference expected"));
1234                 has_dash_dash = 1; /* helps disambiguate */
1235         }
1236
1237         arg = argv[0];
1238         dash_dash_pos = -1;
1239         for (i = 0; i < argc; i++) {
1240                 if (opts->accept_pathspec && !strcmp(argv[i], "--")) {
1241                         dash_dash_pos = i;
1242                         break;
1243                 }
1244         }
1245         if (dash_dash_pos == 0)
1246                 return 1; /* case (2) */
1247         else if (dash_dash_pos == 1)
1248                 has_dash_dash = 1; /* case (3) or (1) */
1249         else if (dash_dash_pos >= 2)
1250                 die(_("only one reference expected, %d given."), dash_dash_pos);
1251         opts->count_checkout_paths = !opts->quiet && !has_dash_dash;
1252
1253         if (!strcmp(arg, "-"))
1254                 arg = "@{-1}";
1255
1256         if (get_oid_mb(arg, rev)) {
1257                 /*
1258                  * Either case (3) or (4), with <something> not being
1259                  * a commit, or an attempt to use case (1) with an
1260                  * invalid ref.
1261                  *
1262                  * It's likely an error, but we need to find out if
1263                  * we should auto-create the branch, case (3).(b).
1264                  */
1265                 int recover_with_dwim = dwim_new_local_branch_ok;
1266
1267                 int could_be_checkout_paths = !has_dash_dash &&
1268                         check_filename(opts->prefix, arg);
1269
1270                 if (!has_dash_dash && !no_wildcard(arg))
1271                         recover_with_dwim = 0;
1272
1273                 /*
1274                  * Accept "git checkout foo", "git checkout foo --"
1275                  * and "git switch foo" as candidates for dwim.
1276                  */
1277                 if (!(argc == 1 && !has_dash_dash) &&
1278                     !(argc == 2 && has_dash_dash) &&
1279                     opts->accept_pathspec)
1280                         recover_with_dwim = 0;
1281
1282                 if (recover_with_dwim) {
1283                         const char *remote = parse_remote_branch(arg, rev,
1284                                                                  could_be_checkout_paths);
1285                         if (remote) {
1286                                 *new_branch = arg;
1287                                 arg = remote;
1288                                 /* DWIMmed to create local branch, case (3).(b) */
1289                         } else {
1290                                 recover_with_dwim = 0;
1291                         }
1292                 }
1293
1294                 if (!recover_with_dwim) {
1295                         if (has_dash_dash)
1296                                 die(_("invalid reference: %s"), arg);
1297                         return argcount;
1298                 }
1299         }
1300
1301         /* we can't end up being in (2) anymore, eat the argument */
1302         argcount++;
1303         argv++;
1304         argc--;
1305
1306         setup_new_branch_info_and_source_tree(new_branch_info, opts, rev, arg);
1307
1308         if (!opts->source_tree)                   /* case (1): want a tree */
1309                 die(_("reference is not a tree: %s"), arg);
1310
1311         if (!has_dash_dash) {   /* case (3).(d) -> (1) */
1312                 /*
1313                  * Do not complain the most common case
1314                  *      git checkout branch
1315                  * even if there happen to be a file called 'branch';
1316                  * it would be extremely annoying.
1317                  */
1318                 if (argc)
1319                         verify_non_filename(opts->prefix, arg);
1320         } else if (opts->accept_pathspec) {
1321                 argcount++;
1322                 argv++;
1323                 argc--;
1324         }
1325
1326         return argcount;
1327 }
1328
1329 static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
1330 {
1331         int status;
1332         struct strbuf branch_ref = STRBUF_INIT;
1333
1334         trace2_cmd_mode("unborn");
1335
1336         if (!opts->new_branch)
1337                 die(_("You are on a branch yet to be born"));
1338         strbuf_addf(&branch_ref, "refs/heads/%s", opts->new_branch);
1339         status = create_symref("HEAD", branch_ref.buf, "checkout -b");
1340         strbuf_release(&branch_ref);
1341         if (!opts->quiet)
1342                 fprintf(stderr, _("Switched to a new branch '%s'\n"),
1343                         opts->new_branch);
1344         return status;
1345 }
1346
1347 static void die_expecting_a_branch(const struct branch_info *branch_info)
1348 {
1349         struct object_id oid;
1350         char *to_free;
1351
1352         if (dwim_ref(branch_info->name, strlen(branch_info->name), &oid, &to_free) == 1) {
1353                 const char *ref = to_free;
1354
1355                 if (skip_prefix(ref, "refs/tags/", &ref))
1356                         die(_("a branch is expected, got tag '%s'"), ref);
1357                 if (skip_prefix(ref, "refs/remotes/", &ref))
1358                         die(_("a branch is expected, got remote branch '%s'"), ref);
1359                 die(_("a branch is expected, got '%s'"), ref);
1360         }
1361         if (branch_info->commit)
1362                 die(_("a branch is expected, got commit '%s'"), branch_info->name);
1363         /*
1364          * This case should never happen because we already die() on
1365          * non-commit, but just in case.
1366          */
1367         die(_("a branch is expected, got '%s'"), branch_info->name);
1368 }
1369
1370 static void die_if_some_operation_in_progress(void)
1371 {
1372         struct wt_status_state state;
1373
1374         memset(&state, 0, sizeof(state));
1375         wt_status_get_state(the_repository, &state, 0);
1376
1377         if (state.merge_in_progress)
1378                 die(_("cannot switch branch while merging\n"
1379                       "Consider \"git merge --quit\" "
1380                       "or \"git worktree add\"."));
1381         if (state.am_in_progress)
1382                 die(_("cannot switch branch in the middle of an am session\n"
1383                       "Consider \"git am --quit\" "
1384                       "or \"git worktree add\"."));
1385         if (state.rebase_interactive_in_progress || state.rebase_in_progress)
1386                 die(_("cannot switch branch while rebasing\n"
1387                       "Consider \"git rebase --quit\" "
1388                       "or \"git worktree add\"."));
1389         if (state.cherry_pick_in_progress)
1390                 die(_("cannot switch branch while cherry-picking\n"
1391                       "Consider \"git cherry-pick --quit\" "
1392                       "or \"git worktree add\"."));
1393         if (state.revert_in_progress)
1394                 die(_("cannot switch branch while reverting\n"
1395                       "Consider \"git revert --quit\" "
1396                       "or \"git worktree add\"."));
1397         if (state.bisect_in_progress)
1398                 warning(_("you are switching branch while bisecting"));
1399 }
1400
1401 static int checkout_branch(struct checkout_opts *opts,
1402                            struct branch_info *new_branch_info)
1403 {
1404         if (opts->pathspec.nr)
1405                 die(_("paths cannot be used with switching branches"));
1406
1407         if (opts->patch_mode)
1408                 die(_("'%s' cannot be used with switching branches"),
1409                     "--patch");
1410
1411         if (opts->overlay_mode != -1)
1412                 die(_("'%s' cannot be used with switching branches"),
1413                     "--[no]-overlay");
1414
1415         if (opts->writeout_stage)
1416                 die(_("'%s' cannot be used with switching branches"),
1417                     "--ours/--theirs");
1418
1419         if (opts->force && opts->merge)
1420                 die(_("'%s' cannot be used with '%s'"), "-f", "-m");
1421
1422         if (opts->discard_changes && opts->merge)
1423                 die(_("'%s' cannot be used with '%s'"), "--discard-changes", "--merge");
1424
1425         if (opts->force_detach && opts->new_branch)
1426                 die(_("'%s' cannot be used with '%s'"),
1427                     "--detach", "-b/-B/--orphan");
1428
1429         if (opts->new_orphan_branch) {
1430                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1431                         die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
1432                 if (opts->orphan_from_empty_tree && new_branch_info->name)
1433                         die(_("'%s' cannot take <start-point>"), "--orphan");
1434         } else if (opts->force_detach) {
1435                 if (opts->track != BRANCH_TRACK_UNSPECIFIED)
1436                         die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
1437         } else if (opts->track == BRANCH_TRACK_UNSPECIFIED)
1438                 opts->track = git_branch_track;
1439
1440         if (new_branch_info->name && !new_branch_info->commit)
1441                 die(_("Cannot switch branch to a non-commit '%s'"),
1442                     new_branch_info->name);
1443
1444         if (!opts->switch_branch_doing_nothing_is_ok &&
1445             !new_branch_info->name &&
1446             !opts->new_branch &&
1447             !opts->force_detach)
1448                 die(_("missing branch or commit argument"));
1449
1450         if (!opts->implicit_detach &&
1451             !opts->force_detach &&
1452             !opts->new_branch &&
1453             !opts->new_branch_force &&
1454             new_branch_info->name &&
1455             !new_branch_info->path)
1456                 die_expecting_a_branch(new_branch_info);
1457
1458         if (!opts->can_switch_when_in_progress)
1459                 die_if_some_operation_in_progress();
1460
1461         if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
1462             !opts->ignore_other_worktrees) {
1463                 int flag;
1464                 char *head_ref = resolve_refdup("HEAD", 0, NULL, &flag);
1465                 if (head_ref &&
1466                     (!(flag & REF_ISSYMREF) || strcmp(head_ref, new_branch_info->path)))
1467                         die_if_checked_out(new_branch_info->path, 1);
1468                 free(head_ref);
1469         }
1470
1471         if (!new_branch_info->commit && opts->new_branch) {
1472                 struct object_id rev;
1473                 int flag;
1474
1475                 if (!read_ref_full("HEAD", 0, &rev, &flag) &&
1476                     (flag & REF_ISSYMREF) && is_null_oid(&rev))
1477                         return switch_unborn_to_new_branch(opts);
1478         }
1479         return switch_branches(opts, new_branch_info);
1480 }
1481
1482 static struct option *add_common_options(struct checkout_opts *opts,
1483                                          struct option *prevopts)
1484 {
1485         struct option options[] = {
1486                 OPT__QUIET(&opts->quiet, N_("suppress progress reporting")),
1487                 OPT_CALLBACK_F(0, "recurse-submodules", NULL,
1488                             "checkout", "control recursive updating of submodules",
1489                             PARSE_OPT_OPTARG, option_parse_recurse_submodules_worktree_updater),
1490                 OPT_BOOL(0, "progress", &opts->show_progress, N_("force progress reporting")),
1491                 OPT_BOOL('m', "merge", &opts->merge, N_("perform a 3-way merge with the new branch")),
1492                 OPT_STRING(0, "conflict", &opts->conflict_style, N_("style"),
1493                            N_("conflict style (merge or diff3)")),
1494                 OPT_END()
1495         };
1496         struct option *newopts = parse_options_concat(prevopts, options);
1497         free(prevopts);
1498         return newopts;
1499 }
1500
1501 static struct option *add_common_switch_branch_options(
1502         struct checkout_opts *opts, struct option *prevopts)
1503 {
1504         struct option options[] = {
1505                 OPT_BOOL('d', "detach", &opts->force_detach, N_("detach HEAD at named commit")),
1506                 OPT_SET_INT('t', "track",  &opts->track, N_("set upstream info for new branch"),
1507                         BRANCH_TRACK_EXPLICIT),
1508                 OPT__FORCE(&opts->force, N_("force checkout (throw away local modifications)"),
1509                            PARSE_OPT_NOCOMPLETE),
1510                 OPT_STRING(0, "orphan", &opts->new_orphan_branch, N_("new-branch"), N_("new unparented branch")),
1511                 OPT_BOOL_F(0, "overwrite-ignore", &opts->overwrite_ignore,
1512                            N_("update ignored files (default)"),
1513                            PARSE_OPT_NOCOMPLETE),
1514                 OPT_BOOL(0, "ignore-other-worktrees", &opts->ignore_other_worktrees,
1515                          N_("do not check if another worktree is holding the given ref")),
1516                 OPT_END()
1517         };
1518         struct option *newopts = parse_options_concat(prevopts, options);
1519         free(prevopts);
1520         return newopts;
1521 }
1522
1523 static struct option *add_checkout_path_options(struct checkout_opts *opts,
1524                                                 struct option *prevopts)
1525 {
1526         struct option options[] = {
1527                 OPT_SET_INT_F('2', "ours", &opts->writeout_stage,
1528                               N_("checkout our version for unmerged files"),
1529                               2, PARSE_OPT_NONEG),
1530                 OPT_SET_INT_F('3', "theirs", &opts->writeout_stage,
1531                               N_("checkout their version for unmerged files"),
1532                               3, PARSE_OPT_NONEG),
1533                 OPT_BOOL('p', "patch", &opts->patch_mode, N_("select hunks interactively")),
1534                 OPT_BOOL(0, "ignore-skip-worktree-bits", &opts->ignore_skipworktree,
1535                          N_("do not limit pathspecs to sparse entries only")),
1536                 OPT_PATHSPEC_FROM_FILE(&opts->pathspec_from_file),
1537                 OPT_PATHSPEC_FILE_NUL(&opts->pathspec_file_nul),
1538                 OPT_END()
1539         };
1540         struct option *newopts = parse_options_concat(prevopts, options);
1541         free(prevopts);
1542         return newopts;
1543 }
1544
1545 /* create-branch option (either b or c) */
1546 static char cb_option = 'b';
1547
1548 static int checkout_main(int argc, const char **argv, const char *prefix,
1549                          struct checkout_opts *opts, struct option *options,
1550                          const char * const usagestr[])
1551 {
1552         struct branch_info new_branch_info;
1553         int parseopt_flags = 0;
1554
1555         memset(&new_branch_info, 0, sizeof(new_branch_info));
1556         opts->overwrite_ignore = 1;
1557         opts->prefix = prefix;
1558         opts->show_progress = -1;
1559
1560         git_config(git_checkout_config, opts);
1561
1562         opts->track = BRANCH_TRACK_UNSPECIFIED;
1563
1564         if (!opts->accept_pathspec && !opts->accept_ref)
1565                 BUG("make up your mind, you need to take _something_");
1566         if (opts->accept_pathspec && opts->accept_ref)
1567                 parseopt_flags = PARSE_OPT_KEEP_DASHDASH;
1568
1569         argc = parse_options(argc, argv, prefix, options,
1570                              usagestr, parseopt_flags);
1571
1572         if (opts->show_progress < 0) {
1573                 if (opts->quiet)
1574                         opts->show_progress = 0;
1575                 else
1576                         opts->show_progress = isatty(2);
1577         }
1578
1579         if (opts->conflict_style) {
1580                 opts->merge = 1; /* implied */
1581                 git_xmerge_config("merge.conflictstyle", opts->conflict_style, NULL);
1582         }
1583         if (opts->force) {
1584                 opts->discard_changes = 1;
1585                 opts->ignore_unmerged_opt = "--force";
1586                 opts->ignore_unmerged = 1;
1587         }
1588
1589         if ((!!opts->new_branch + !!opts->new_branch_force + !!opts->new_orphan_branch) > 1)
1590                 die(_("-%c, -%c and --orphan are mutually exclusive"),
1591                                 cb_option, toupper(cb_option));
1592
1593         if (opts->overlay_mode == 1 && opts->patch_mode)
1594                 die(_("-p and --overlay are mutually exclusive"));
1595
1596         if (opts->checkout_index >= 0 || opts->checkout_worktree >= 0) {
1597                 if (opts->checkout_index < 0)
1598                         opts->checkout_index = 0;
1599                 if (opts->checkout_worktree < 0)
1600                         opts->checkout_worktree = 0;
1601         } else {
1602                 if (opts->checkout_index < 0)
1603                         opts->checkout_index = -opts->checkout_index - 1;
1604                 if (opts->checkout_worktree < 0)
1605                         opts->checkout_worktree = -opts->checkout_worktree - 1;
1606         }
1607         if (opts->checkout_index < 0 || opts->checkout_worktree < 0)
1608                 BUG("these flags should be non-negative by now");
1609         /*
1610          * convenient shortcut: "git restore --staged [--worktree]" equals
1611          * "git restore --staged [--worktree] --source HEAD"
1612          */
1613         if (!opts->from_treeish && opts->checkout_index)
1614                 opts->from_treeish = "HEAD";
1615
1616         /*
1617          * From here on, new_branch will contain the branch to be checked out,
1618          * and new_branch_force and new_orphan_branch will tell us which one of
1619          * -b/-B/-c/-C/--orphan is being used.
1620          */
1621         if (opts->new_branch_force)
1622                 opts->new_branch = opts->new_branch_force;
1623
1624         if (opts->new_orphan_branch)
1625                 opts->new_branch = opts->new_orphan_branch;
1626
1627         /* --track without -c/-C/-b/-B/--orphan should DWIM */
1628         if (opts->track != BRANCH_TRACK_UNSPECIFIED && !opts->new_branch) {
1629                 const char *argv0 = argv[0];
1630                 if (!argc || !strcmp(argv0, "--"))
1631                         die(_("--track needs a branch name"));
1632                 skip_prefix(argv0, "refs/", &argv0);
1633                 skip_prefix(argv0, "remotes/", &argv0);
1634                 argv0 = strchr(argv0, '/');
1635                 if (!argv0 || !argv0[1])
1636                         die(_("missing branch name; try -%c"), cb_option);
1637                 opts->new_branch = argv0 + 1;
1638         }
1639
1640         /*
1641          * Extract branch name from command line arguments, so
1642          * all that is left is pathspecs.
1643          *
1644          * Handle
1645          *
1646          *  1) git checkout <tree> -- [<paths>]
1647          *  2) git checkout -- [<paths>]
1648          *  3) git checkout <something> [<paths>]
1649          *
1650          * including "last branch" syntax and DWIM-ery for names of
1651          * remote branches, erroring out for invalid or ambiguous cases.
1652          */
1653         if (argc && opts->accept_ref) {
1654                 struct object_id rev;
1655                 int dwim_ok =
1656                         !opts->patch_mode &&
1657                         opts->dwim_new_local_branch &&
1658                         opts->track == BRANCH_TRACK_UNSPECIFIED &&
1659                         !opts->new_branch;
1660                 int n = parse_branchname_arg(argc, argv, dwim_ok,
1661                                              &new_branch_info, opts, &rev);
1662                 argv += n;
1663                 argc -= n;
1664         } else if (!opts->accept_ref && opts->from_treeish) {
1665                 struct object_id rev;
1666
1667                 if (get_oid_mb(opts->from_treeish, &rev))
1668                         die(_("could not resolve %s"), opts->from_treeish);
1669
1670                 setup_new_branch_info_and_source_tree(&new_branch_info,
1671                                                       opts, &rev,
1672                                                       opts->from_treeish);
1673
1674                 if (!opts->source_tree)
1675                         die(_("reference is not a tree: %s"), opts->from_treeish);
1676         }
1677
1678         if (argc) {
1679                 parse_pathspec(&opts->pathspec, 0,
1680                                opts->patch_mode ? PATHSPEC_PREFIX_ORIGIN : 0,
1681                                prefix, argv);
1682
1683                 if (!opts->pathspec.nr)
1684                         die(_("invalid path specification"));
1685
1686                 /*
1687                  * Try to give more helpful suggestion.
1688                  * new_branch && argc > 1 will be caught later.
1689                  */
1690                 if (opts->new_branch && argc == 1 && !new_branch_info.commit)
1691                         die(_("'%s' is not a commit and a branch '%s' cannot be created from it"),
1692                                 argv[0], opts->new_branch);
1693
1694                 if (opts->force_detach)
1695                         die(_("git checkout: --detach does not take a path argument '%s'"),
1696                             argv[0]);
1697         }
1698
1699         if (opts->pathspec_from_file) {
1700                 if (opts->pathspec.nr)
1701                         die(_("--pathspec-from-file is incompatible with pathspec arguments"));
1702
1703                 if (opts->force_detach)
1704                         die(_("--pathspec-from-file is incompatible with --detach"));
1705
1706                 if (opts->patch_mode)
1707                         die(_("--pathspec-from-file is incompatible with --patch"));
1708
1709                 parse_pathspec_file(&opts->pathspec, 0,
1710                                     0,
1711                                     prefix, opts->pathspec_from_file, opts->pathspec_file_nul);
1712         } else if (opts->pathspec_file_nul) {
1713                 die(_("--pathspec-file-nul requires --pathspec-from-file"));
1714         }
1715
1716         if (opts->pathspec.nr) {
1717                 if (1 < !!opts->writeout_stage + !!opts->force + !!opts->merge)
1718                         die(_("git checkout: --ours/--theirs, --force and --merge are incompatible when\n"
1719                               "checking out of the index."));
1720         } else {
1721                 if (opts->accept_pathspec && !opts->empty_pathspec_ok &&
1722                     !opts->patch_mode)  /* patch mode is special */
1723                         die(_("you must specify path(s) to restore"));
1724         }
1725
1726         if (opts->new_branch) {
1727                 struct strbuf buf = STRBUF_INIT;
1728
1729                 if (opts->new_branch_force)
1730                         opts->branch_exists = validate_branchname(opts->new_branch, &buf);
1731                 else
1732                         opts->branch_exists =
1733                                 validate_new_branchname(opts->new_branch, &buf, 0);
1734                 strbuf_release(&buf);
1735         }
1736
1737         UNLEAK(opts);
1738         if (opts->patch_mode || opts->pathspec.nr)
1739                 return checkout_paths(opts, &new_branch_info);
1740         else
1741                 return checkout_branch(opts, &new_branch_info);
1742 }
1743
1744 int cmd_checkout(int argc, const char **argv, const char *prefix)
1745 {
1746         struct checkout_opts opts;
1747         struct option *options;
1748         struct option checkout_options[] = {
1749                 OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
1750                            N_("create and checkout a new branch")),
1751                 OPT_STRING('B', NULL, &opts.new_branch_force, N_("branch"),
1752                            N_("create/reset and checkout a branch")),
1753                 OPT_BOOL('l', NULL, &opts.new_branch_log, N_("create reflog for new branch")),
1754                 OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
1755                          N_("second guess 'git checkout <no-such-branch>' (default)")),
1756                 OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode (default)")),
1757                 OPT_END()
1758         };
1759         int ret;
1760
1761         memset(&opts, 0, sizeof(opts));
1762         opts.dwim_new_local_branch = 1;
1763         opts.switch_branch_doing_nothing_is_ok = 1;
1764         opts.only_merge_on_switching_branches = 0;
1765         opts.accept_ref = 1;
1766         opts.accept_pathspec = 1;
1767         opts.implicit_detach = 1;
1768         opts.can_switch_when_in_progress = 1;
1769         opts.orphan_from_empty_tree = 0;
1770         opts.empty_pathspec_ok = 1;
1771         opts.overlay_mode = -1;
1772         opts.checkout_index = -2;    /* default on */
1773         opts.checkout_worktree = -2; /* default on */
1774
1775         if (argc == 3 && !strcmp(argv[1], "-b")) {
1776                 /*
1777                  * User ran 'git checkout -b <branch>' and expects
1778                  * the same behavior as 'git switch -c <branch>'.
1779                  */
1780                 opts.switch_branch_doing_nothing_is_ok = 0;
1781                 opts.only_merge_on_switching_branches = 1;
1782         }
1783
1784         options = parse_options_dup(checkout_options);
1785         options = add_common_options(&opts, options);
1786         options = add_common_switch_branch_options(&opts, options);
1787         options = add_checkout_path_options(&opts, options);
1788
1789         ret = checkout_main(argc, argv, prefix, &opts,
1790                             options, checkout_usage);
1791         FREE_AND_NULL(options);
1792         return ret;
1793 }
1794
1795 int cmd_switch(int argc, const char **argv, const char *prefix)
1796 {
1797         struct checkout_opts opts;
1798         struct option *options = NULL;
1799         struct option switch_options[] = {
1800                 OPT_STRING('c', "create", &opts.new_branch, N_("branch"),
1801                            N_("create and switch to a new branch")),
1802                 OPT_STRING('C', "force-create", &opts.new_branch_force, N_("branch"),
1803                            N_("create/reset and switch to a branch")),
1804                 OPT_BOOL(0, "guess", &opts.dwim_new_local_branch,
1805                          N_("second guess 'git switch <no-such-branch>'")),
1806                 OPT_BOOL(0, "discard-changes", &opts.discard_changes,
1807                          N_("throw away local modifications")),
1808                 OPT_END()
1809         };
1810         int ret;
1811
1812         memset(&opts, 0, sizeof(opts));
1813         opts.dwim_new_local_branch = 1;
1814         opts.accept_ref = 1;
1815         opts.accept_pathspec = 0;
1816         opts.switch_branch_doing_nothing_is_ok = 0;
1817         opts.only_merge_on_switching_branches = 1;
1818         opts.implicit_detach = 0;
1819         opts.can_switch_when_in_progress = 0;
1820         opts.orphan_from_empty_tree = 1;
1821         opts.overlay_mode = -1;
1822
1823         options = parse_options_dup(switch_options);
1824         options = add_common_options(&opts, options);
1825         options = add_common_switch_branch_options(&opts, options);
1826
1827         cb_option = 'c';
1828
1829         ret = checkout_main(argc, argv, prefix, &opts,
1830                             options, switch_branch_usage);
1831         FREE_AND_NULL(options);
1832         return ret;
1833 }
1834
1835 int cmd_restore(int argc, const char **argv, const char *prefix)
1836 {
1837         struct checkout_opts opts;
1838         struct option *options;
1839         struct option restore_options[] = {
1840                 OPT_STRING('s', "source", &opts.from_treeish, "<tree-ish>",
1841                            N_("which tree-ish to checkout from")),
1842                 OPT_BOOL('S', "staged", &opts.checkout_index,
1843                            N_("restore the index")),
1844                 OPT_BOOL('W', "worktree", &opts.checkout_worktree,
1845                            N_("restore the working tree (default)")),
1846                 OPT_BOOL(0, "ignore-unmerged", &opts.ignore_unmerged,
1847                          N_("ignore unmerged entries")),
1848                 OPT_BOOL(0, "overlay", &opts.overlay_mode, N_("use overlay mode")),
1849                 OPT_END()
1850         };
1851         int ret;
1852
1853         memset(&opts, 0, sizeof(opts));
1854         opts.accept_ref = 0;
1855         opts.accept_pathspec = 1;
1856         opts.empty_pathspec_ok = 0;
1857         opts.overlay_mode = 0;
1858         opts.checkout_index = -1;    /* default off */
1859         opts.checkout_worktree = -2; /* default on */
1860         opts.ignore_unmerged_opt = "--ignore-unmerged";
1861
1862         options = parse_options_dup(restore_options);
1863         options = add_common_options(&opts, options);
1864         options = add_checkout_path_options(&opts, options);
1865
1866         ret = checkout_main(argc, argv, prefix, &opts,
1867                             options, restore_usage);
1868         FREE_AND_NULL(options);
1869         return ret;
1870 }